The anterior segment of the eye includes structures in front of the vitreous humor, including the cornea, iris, ciliary body, and crystalline lens. Common anterior segment disorders include cataracts and refractive errors in the cornea.
Ophthalmic surgeons may use photodisruptive laser technology in cataract and corneal procedures to improve accuracy, safety, and patient outcomes. For example, femtosecond laser systems may be used in cataract surgery for capsulorhexis and lens fragmentation via laser-induced photodisruption. Femtosecond lasers may also be used in corneal applications, such as corneal flap creation for LASIK. The LenSx® Laser System available from Alcon is an example of a femtosecond laser system that may be employed in both cataract and corneal surgical procedures. Laser systems used in a cataract procedure typically include a laser engine, an optical head unit, a dedicated OCT system and imaging device for targeting tissue and cut patterns, a monitor, and various user input mechanisms.
After a laser portion of a cataract procedure is complete, the surgeon may perform a manual procedure to remove the fragmented lens and insert an intraocular lens (IOL). In general, surgical laser systems are stand-alone systems that are functionally and structurally separate from equipment used by a surgeon during manual surgical procedures, which often includes non-sterile and sterile preparation areas, a high-resolution stereo surgical microscope, an OCT system, imaging devices, display monitors, and instrumentation for anesthesiology
Due to their substantial size, it is difficult to arrange both laser and manual surgical equipment around a patient in a single operating room. An operating room for laser-assisted cataract surgery typically needs to accommodate at least five individuals: a patient, the operating surgeon, two assistants, and anesthesiologist. Moreover, the operating room must accommodate the above-referenced instruments, as well as surgical scalpels, tweezers and scissors, a manually held phacoemulsification hand-piece piece with tubing connected to a console, and an intra-ocular lens (IOL) injection device. Thus, ophthalmic surgeons often require two rooms or dedicated spaces to perform a cataract procedure—one for the laser system and procedure, and another for the manual procedure and associated instruments. Patients may be initially situated in one area beneath a laser surgical system for the laser portion of a procedure, then moved to another area beneath a surgical microscope for the manual part of the procedure. This increases the time and cost of the surgery.
Accordingly, there is a need to integrate the equipment used in a laser and manual ophthalmic surgical procedures to streamline surgeries, reduce the amount of floor space required, and eliminate costly duplicative equipment, such as OCT systems. However, properly integrating such equipment presents many challenges.
For example, the surgeon's tools require not only sufficient floor space around a patient, but a working distance under the surgical microscope and any attached imaging device. The working distance must be sufficient to permit the surgeon to perform a manual cataract procedure, but must abide the capabilities of the microscope and accommodate a comfortable posture for the surgeon. A surgeon's typical working distance (e.g., 150-300 mm) may be comparable to or smaller than the depth of a surgical laser optical head. Thus, even temporarily positioning a surgical laser optical head between a microscope and the patient's head is problematic because, in addition to the space needed for the optical head itself, additional room is needed to safely dock and maneuver the laser surgical unit very close to the patient's face and eye. But, simply increasing the working distance of a surgical microscope to accommodate a laser optical head may necessitate higher aperture optics, increased complexity, and additional costs, and may make it more difficult for a surgeon to comfortably position himself or herself during a procedure.
Integrating OCT systems used in the laser and manual portions of a procedure presents additional challenges. For instance, typically each OCT system will optimally operate at the near-infrared optical wavelength region to avoid the light being visible to the patient and the tissue being transparent. When OCT is used for pre- and post-operative diagnosis of the refractive properties of the eye, a broad bandwidth OCT light source is necessary to achieve several microns spatial resolution. The bandwidth necessary to achieve this resolution is around 100 nm or more. Most femtosecond lasers appropriate for ophthalmic surgery employs Ytterbium gain material because of their superior properties and advanced technology and operative in the wavelength band of 1025 to 1055 nm. When the two wavelength bands overlap and the light traverses parts of the same optical components, it may be problematic to separate the light beams of the two subsystems and avoid interference.
Another difficulty in integrating subsystems lies in the increased mass of the components of the integrated system, which connect to the eye of the patient. As the integrated components become heavier and bulkier, it is more difficult to safely attach them to the patient's eye and avoid mechanical injury. Systems which attempt to avoid this issue by operating in an undocked state (i.e., not attached to the eye) typically require an active eye tracking device, which increase complexity and cost and, due to involuntary eye movements, may limit the time of laser treatment to a fraction of a second. When the laser treatment time is limited, available treatment options are also limited to a subset of treatments otherwise available with a femtosecond laser. Indeed, laser treatment for cataract surgery may require incisions inside the lens and laser fragmentation of cataractous lens tissue, which may require treatment times well beyond the ability for a patient to voluntarily hold his eye steady (typically 1 second or less). Additionally optical corneal incisions, entry cuts, and arcuate incisions, may further increase the both the time and precision requirements of a laser surgical cut.
The present disclosure aims to solve these and other challenges with an integrated ophthalmic surgical system, as described herein.